All US flights could in future carry an armed "Sky Marshal" as part of a huge range of measures designed to thwart future hijackers

"I could just as easily cut your throat with a credit card"

Former El Al security chief on new knife ban

The marshal idea - already used by the Israeli airline El Al - emerged during emergency congressional debates aimed at the establishment of a US national task force to direct the "war on terrorism".

More immediate security plans announced by the US Federal Aviation Administration include increased numbers of uniformed security guards and "hundreds" of extra FBI agents at airports.

There is also an end to "walk-on" and advanced check-ins at hotels, and all aircraft are undergoing lengthy searches before take-off.

Silence

Many US airports yesterday were eerily silent. Los Angeles, the world's third busiest, was almost deserted.

At Logan Airport in Boston - take-off point for the hijacked WTC planes - tow-trucks arrived to start the work of removing more than 2,000 vehicles from the airport car park.

This morning a spokesman for Logan said security work needed before the airport could re-open was "about half-complete".

Some of the new security measures are being kept secret. But steps officially announced include increased use of sniffer dogs and bomb-detecting equipment; use of hand-held metal detectors; random ID checks on both passengers and airport staff; and a ban on allowing visitors into secure areas to meet passengers on arrival.

Cost

But there are no plans for a complete ban on hand luggage, as recommended by some security experts.

Instead the FAA has ordered introduction of full "baggage reconciliation" - the matching of all luggage to passengers.

This means that a bag will no longer be allowed onto a plane unless the passenger is already aboard.

This is the time-consuming and costly procedure which, industry critics say, the airline industry opposed after it was proposed by the previous US administration.

All knives and cutting tools - including nail files and rounded butter knives - will now be banned. Sharp steak knives for in-flight meals will no longer be used.

Ban ignored

Previously knives with blades less than four inches long - such as pen-knives - were allowed.

But, according to reports, restrictions like this were routinely ignored. Numerous witnesses have come forward to say that had little difficulty innocently taking banned items - ranging from grenade-like gas canisters to bullet proof jackets - onto internal US flights.

The new, tighter ban will now be strcitly enforced. But some remain pessimistic believing that security measures can never totally foil determined terrorists.

Former head of security at El Al Shlomo Dror - now at the Israeli defence ministry - said today of the ban on knives: "I could cut you throat just as easily with a credit card".

El Al's improved security record, experts believe, is based on the presence of armed, plain-clothes security officers on flights. According to reports the US Justice Department is considering the introduction of similar armed "Sky Marshals".